1. A neuron synapse is an example of paracrine signaling. False- neural
2. Neurons in the anterior pituitary secrete hormones in response to tropic hormones. True.
3. Amino acid derivatives are hydrophobic and act through receptors like G-protein coupled receptors.
False- hydrophilic.
4. Tropic hormones directly stimulate gene transcription in target cells. False-hormone release.
5. Antidiuretic hormone is released from the posterior pituitary gland. True.
6. Luteinizing hormone acts in both males and females to cause the release of sex hormones. True.
7. All hormones are released into the bloodstream because of neural stimulation. False- some
triggered by tropic hormones.
8. Progesterone and estrogen are estradiols. False- Estradiol and progesterone are estrogens.
9. Leptin is released from adipocytes and signals satiety. True.
10. The hypothalamus affects the anterior pituitary through paracrine signaling. False: neurohormone.
11. Cortisol release is triggered by a hormone from the posterior pituitary. False- anterior.
12. Thyroid hormones are responsible for growth, development and metabolism regulation. True.
13. Steroid hormones enter the cell and directly bind a hormone response element, triggering
transcription. False- they bind a receptor, and the complex binds the response element.
14. All hormone receptor proteins are allosteric proteins. True.
15. One effect of cortisol is to upregulate gluconeogenesis. True.
16. Receptor proteins for hydrophilic hormones act by allowing the hormone to enter the cell. Falsethey cause a change in conformation inside the cell to release a second messenger.
17. Hydrophilic hormone signals are amplified to a much greater extent than hydrophobic hormone
signals. True.
1. You inject lab mice with two different hormones. One is a steroid, the other is an amino acid
derivative. Which do you expect to have an effect with the smallest concentration? Why?
a. Hydrophilic hormones must bind a receptor to signal in the cell. Most receptor mediated
pathways include amplification steps, allowing a tiny amount of signal to have a large effect.
Steroids, by contrast, enter the cell directly and often have much simpler pathways with less
opportunity for amplification. Therefore, the amino acid derivative will probably have its effect
at a lower concentration than the steroid will.
2. Compare and contrast the short term and long term stress responses.
Short term
Long term
Medulla
Cortex
Sympathetic nervous system
Sympathetic nervous system
Epinephrine, norepinepherine
Corticosteroids: glucocorticoids,
mineralocorticoids, cortisol, aldosterone,
Few minute halflife
Long-lasting
Increase blood to brain, heart muscles; decrease
Increase water reabsorption in kidneys to increase
blood to digestive system. Increase blood pressure, blood volume and blood pressure, release fatty
cardiac output, alertness, breathing rate.
acids into blood stream, gluconeogenesis (in liver
Conversion of glycogen to glucose.
from aa), lower immune response, pain, swelling.
Use G-protein coupled receptor
Bind receptors inside cells, begin protein synthesis
Amino acid derivatives
Steroids
3. Compare and contrast the mode of action of steroid hormones versus hydrophilic hormones like
amino acid derivatives and polypeptides.
a. Steroid hormones enter the cell by diffusion through the cell membrane. They then regulate
gene transcription. They take a long time to act. Hydrophilic hormones cannot enter the cell and
thus bind receptor proteins, notably G-protein coupled receptors. They have a variety of effects,
tending to activate proteins already present in the cell or stimulate secretion of stuff already
present.
4. Compare and contrast the anterior and posterior pituitary glands.
a. The posterior pituitary contains the axon terminals of neurosecretary cells whose bodies are in
the hypothalamus. Hormones released from the posterior pituitary are stimulated by neural
impulse. Posterior releases ADH, oxytocin. Anterior pituitary is not neutrally linked to the
hypothalamus, but contains many blood vessels. Neurons in the hypothalamus release ______
releasing hormone into the blood (a tropic hormone). Receptors on cells in the anterior pituitary
bind these hormone molecules and release their own hormone into the blood stream. They
release adrenocorticotropic hormone, FSH, LH, growth hormone, prolactin, and thyroid
stimulating hormone. BOTH are under the control of the brain and of nerves in the
hypothalamus. BOTH are subject to feedback inhibition. BOTH release products into the
bloodstream.
5. Many professional athletes receive cortisone shots (a cortisol) when they are injured, allowing them
to continue to compete. Why is this steroid not given orally as a long-term treatment for arthritis?
a. Cortisol has many other effects, including depressing the immune system and increasing the
availability of fatty acids for cellular metabolism. When given long-term and distributed through
the circulatory system, it depresses the immune system. People (especially the elderly and
otherwise vulnerable to infection) should not be chronically immunocompromised. Therefore,
other treatments are preferred.
6. For this list of hormones, make a table stating where each is released from, how its release is
triggered, its target organ(s) and what effects it has on the body. Focus on the ones covered in
multiple units (like insulin, which we studied with digestion.)
Where released
How release
Target organ
Effect
Epinephrine
from
triggered
Adrenal gland
Sympathetic
medulla
nervous system
Variety
Cause a shortterm stress
response
Corticosteriods
Adrenal gland
Receipt of
cortex
Adrenocorticotropic
Variety
Long term stress
response
hormone
Androgens
Estrogens
Antidiuretic
Male
Receipt of follicle
reproductive
stimulating
system
hormones
Female
Receipt of follicle
reproductive
stimulating
system
hormones
Posterior pituitary
Stimulation by
hormone
erythropoietin
Variety
specific genes
Variety
Low blood oxygen
Turn on femalespecific genes
Kidneys
hypothalamus
Kidneys
Turn on male-
Insert aquaporins
in collecting ducts
Bone marrow
Make more red
blood cells
Adrenocorticotropic
Anterior pituitary
Signal from
Adrenal gland
Stimulate release
hypothalamus
medulla
of corticosteroids.
Hypothalamus
Signal from brain
Anterior pituitary
Release ACTH
Pancreas
High blood sugar
Variety
Increase glucose
hormone
Corticotrophin
releasing hormone
Insulin
uptake
glucagon
Pancreas
Low blood sugar
Liver
Convert glycogen
to glucose
Luteinizing
Anterior pituitary
hormone
Signal from
Female
Regulate
hypothalamus
reproductive
menstrual cycle
system
Follicle-stimulating
Anterior pituitary
hormone
Prolactin
Anterior pituitary
Signal from
Reproductive
Release of sex
hypothalamus
system
hormones
Signal from
Mammary glands
Growth and milk
hypothalamus
Thyroid stimulating
Anterior pituitary
hormone
Oxytocin
Signal from
production
Thyroid gland
Hormone release
Stimulation by
Female
Labor and milk
hypothalamus
reproductive
production
hypothalamus
Posterior pituitary
system
Growth hormone
Anterior pituitary
Signal from
hypothalamus
Variety
Growth